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ACTIVE CONTROL OF DYNAM IC RESPONSE OF LARGE DEFLECTION PLATES WITH PIEZO ELECTRIC ACTUATORS USING FINITE ELEMENT METHOD
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作者 高坚新 沈亚鹏 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1999年第4期197-204,221,共9页
The transientbehaviorofisotropic and hom ogeneousplateshasbeen a subjectofinterest. Thepresentinvestigation isconcerned w ith the largedeflection transientanalysisand controlofplates w ith piezoelectricsensorsand ac... The transientbehaviorofisotropic and hom ogeneousplateshasbeen a subjectofinterest. Thepresentinvestigation isconcerned w ith the largedeflection transientanalysisand controlofplates w ith piezoelectricsensorsand actuatorsunderapplied transverse loads. In this paper, the increm ental finite elem entequationsconsidering thegeom etricnonlinearity ofpiezoelectricsm artstructuresarede- veloped based on TotalLagrange approach by using the virtualvelocity increm entalvariationalprinci- ples. A four-node Mindlin plate elem ent w ith reduced and selective integration is adopted. The re- sulting increm entequationsare solved by using New m ark'sdirectintegration approach. Transientre- sponse ofplatesw ith piezoelectricsensorsand actuators subjected to transverse dynam ic loading isin- vestigated. The active dam ping isintroduced on the platesby coupling a negativevelocity feedback al- gorithm in a closed controlloop. The num ericalresults show thatpiezoelectric actuators can produce significant dam ping and suppress transient vibration effectively. Finally, the effects of the num ber and locations ofthe piezoelectric actuatorson the controlsystem are also investigated. 展开更多
关键词 geom etrically nonlinearity active control finite elem ent
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A CLASS OF HAMILTONIAN AND EDGE SYMMETRIC CAYLEY GRAPHS ON SYMMETRIC GROUPS 被引量:1
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作者 Wang Shiying\ Zhang Yuren\ Liu Yan 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 1999年第4期492-494,共3页
Let S\-n be the symmetric group, g\++\-i=(123i),g\+-\-i=(1i32) and M\++\-n={g\++\-i∶4≤i≤n}, then M\++\-n is a minimal generating set of S\-n ,where n ≥5.It is proved that Cayley graph Cay( S\-... Let S\-n be the symmetric group, g\++\-i=(123i),g\+-\-i=(1i32) and M\++\-n={g\++\-i∶4≤i≤n}, then M\++\-n is a minimal generating set of S\-n ,where n ≥5.It is proved that Cayley graph Cay( S\-n,M\++\-n∪M\+-\-n) is Hamiltonian and edge symmetric. 展开更多
关键词 Cayley graph Ham iltonian graph edge sym m etric graph sym m etric group
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Matrix-Geometric Method Based Unified Delay Analysis for Wireless Relay Networks
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作者 Liu Juan Chen Wei +1 位作者 Zhang Yingjun(Angela) Cao Zhigang 《China Communications》 SCIE CSCD 2012年第9期61-67,共7页
A lot of work has been focused on desig-ning and analyzing various cooperative diversity pro-tocols for wireless relay networks. To provide a uni-fied queuing analytic framework, we fonmlate an em-bedded Markov chain,... A lot of work has been focused on desig-ning and analyzing various cooperative diversity pro-tocols for wireless relay networks. To provide a uni-fied queuing analytic framework, we fonmlate an em-bedded Markov chain, which rams out to be a Quasi-Birth-and-Death (QBD) process. Using the Matrix-Ce-ometric method, we can analyze the average delay in a unified way. Theoretical analysis is validated by simu-lation results. We show that the delay performances of Amplify-and-Forward or Decode-and-Forwaxd (AF/ DF) and incremental AF/DF schemes can be analyzed in the unified way. Thus, we can always choose the best cooperative diversity scheme in different scenari-os for delay minimization. 展开更多
关键词 wireless relaying tandem queue Mark-ov chain Matrix-Geon'etric method
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NONLINEAR WAVELET SMOOTHING OF ERROR DENSITY IN A SEMIPARAM ETRIC REGRESSION MODEL
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作者 ChaiGenxiang Xu Kejun Dept.ofAppl.Math.,TongjiUniv.,Shanghai200092. 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 1999年第3期329-336,共8页
In this paper,a sem iparam etric regression m odel in w hich errors are i.i.d random variables from an unknow n density f(·) is considered.Based on Hallet al.(1995),a nonlinear w avelet estim ation of f(·)... In this paper,a sem iparam etric regression m odel in w hich errors are i.i.d random variables from an unknow n density f(·) is considered.Based on Hallet al.(1995),a nonlinear w avelet estim ation of f(·) withoutrestrictions ofcontinuity everyw here on f(·) is given,and the convergence rate ofthe estim ators in L2 is obtained. 展开更多
关键词 Sem iparam etric regression error density w avelet nonlinear w avelet estim ation ofdensity.
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FLOW CYTOM ETRIC ANALYSIS OF CELLULAR DNA CONTENT IN EPITHELIAL OVARIAN TUMOR
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作者 温宏武 刘书文 +2 位作者 麦永嫣 严仁英 沈祝萱 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 1992年第2期36-41,共6页
The DNA content of tumor all was analyzed by flow cytometry on parafflnembedded specimens in 73 patients with epithelial ovarian tumor, and its clinical significance was evaluated. One of the 5 benign (20%), 2 of the ... The DNA content of tumor all was analyzed by flow cytometry on parafflnembedded specimens in 73 patients with epithelial ovarian tumor, and its clinical significance was evaluated. One of the 5 benign (20%), 2 of the 11 borderline (18.18%), and 30 of the 57 malignant (52. 63%) tumors were aneuplold. The occurrence rate of aneuploidy In malignant tumors was higher than In benign and borderline tumors ( P < 0. 05 ). Furthermore, aneuploidy was more frequently In the advanced stages (Ⅲ -Ⅳ ) (77. 7%) than in the early stages (Ⅰ - Ⅱ ) (9. 5%) (P<0. 005). The occurrence rate of DNA aneuploidy was higher in patients associated with ascites and the residual tumor≥.2 cm. Patients with aneuploid tumors had more of ten ascites (P<0. 005) and residual tumor size≥2cm (P< 0.005). There was no apparent correlation between the DNA ptoidy and the histologic grade, histologic type of the tumors. G0/G1 cell proportion of DNA diplold tumors in advanced carcinoma (64. 6%) was less than those of early stage carcinoma (75. 9% ) (P<0. 05). The survival rate of diplold tumor patients was higher than that of aneuploid tumor patients in the different time after operation, and the median survival time was 30. 2 months and 10. 3 months, respectively. Multivariate analysis revealed that cellular DNA ploidy was the most Important predictive factor (P = 0. 007) of prognosis, followed by residual tumor size (P= 0. 05). Different tumor specimen of the same patient can exhibit variation sometime (38. 9%).The results revealed that the DNA ploidy may reflect tumor biological characteristics, I. e. , Its proliferative ability. Analysis of cellular DNA content of epithelial ovarian tumors would help us to predict the prognosis of the patients better. 展开更多
关键词 DNA FLOW CYTOM ETRIC ANALYSIS OF CELLULAR DNA CONTENT IN EPITHELIAL OVARIAN TUMOR
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A KIND OF FUZZY LINEAR PROGRAMMING PROBLEMS BASED ON INTERVAL-VALUED FUZZY SETS 被引量:1
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作者 Xu JiupingDept. of Appl.Math.,Sichuan Union University,Chengdu 610065. 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2000年第1期65-72,共8页
The objective of this paper is to deal with a kind of fuzzy linear programming problem based on interval\|valued fuzzy sets (IVFLP) through the medium of procedure that turns IVFLP into parametric linear programming v... The objective of this paper is to deal with a kind of fuzzy linear programming problem based on interval\|valued fuzzy sets (IVFLP) through the medium of procedure that turns IVFLP into parametric linear programming via the mathematical programming.Some useful results for the benefit of solving IVFLP are expounded and proved,developed and discussed.Furthermore,that the proposed techniques in this paper allow the decision\|maker to assign a different degree of importance can provide a useful way to efficiently help the decision\|maker make their decisions. 展开更多
关键词 Fuzzy linear program m ing interval-valued fuzzy sets param etric linear program m ing Fuzzy decision-m aking uncertainty.
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Chiral metal-organic frameworks with tunable catalytic selectivity in asymmetric transfer hydrogenation reactions 被引量:4
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作者 Xu Chen Zhiwei Qiao +6 位作者 Bang Hou Hong Jiang Wei Gong Jinqiao Dong Hai-Yang Li Yong Cui Yan Liu 《Nano Research》 SCIE EI CAS CSCD 2021年第2期466-472,共7页
Metal-organic frameworks(MOFs)have achieved great success in the field of heterogeneous catalysis,however,ifs still challenging to design MOF catalysts with enhanced selectivity.Here,we demonstrated a combination stra... Metal-organic frameworks(MOFs)have achieved great success in the field of heterogeneous catalysis,however,ifs still challenging to design MOF catalysts with enhanced selectivity.Here,we demonstrated a combination strategy of metal design and ligand design on the enantioselectivity—that is the enantioselectivities of chiral MOF(CMOF)catalysts could be significantly enhanced by the rational choice of metal ions with higher electronegativities and introducing sterically demanding groups into the ligands.Four isostructural Ca-,Sr-and Zn-based CMOFs were prepared from enantiopure phosphono-carboxylate ligands of 1,V-biphenol that are functionalized with 2,4,6-trimethyl-and 2,4,6-trifluoro-phenyl groups at the Supposition.The uniformly distributed metal phosphonates along the channels could act as Lewis acids and catalyze the asymmetric transfer hydrogenation of heteroaromatic imines(benzoxazines and quinolines).Particularly,the Ca-based MOF 1 with 2,4,6-trimethyl groups at the substituents exhibited enhanced catalytic performance,affording the highest enantioselectivity(up to 97%).It is also the first report of the heterogeneous catalyst with chiral non-noble metal phosphonate active sites for asymmetric transfer hydrogenation reactions with Hantzsch ester as the hydrogen source.The catalyst design strategy demonstrated here is expected to develop new types of chiral materials for asymmetric catalysis and other chiral applications. 展开更多
关键词 metal-organic frameworks metal phosphonate Lewis acid asymm etric catalysis hydrogenation reaction
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Compact self-standing layered film assembled by V2O5·nH2O/CNTs 2D/1D composites for high volumetric capacitance flexible supercapacitors 被引量:5
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作者 Kai Guo Yiju Li +2 位作者 Chong Li Neng Yu Huiqiao Li 《Science China Materials》 SCIE EI CSCD 2019年第7期936-946,共11页
Flexible supercapacitors (SCs) are attractive energy storage devices for wearable electronics, but their applications are hindered by their low volumetric energy densities. Two dimensional (2D) non-carbon nanomaterial... Flexible supercapacitors (SCs) are attractive energy storage devices for wearable electronics, but their applications are hindered by their low volumetric energy densities. Two dimensional (2D) non-carbon nanomaterials are the most promising pseudocapacitive materials for high volumetric capacitance electrodes. However, they are poorly conductive and prone to self-stacking, which results in unsatisfactory electrochemical performance. In this work, large-scale V2O5·nH2O ultrathin nanosheets are synthesized by a facile and scalable method and transformed into layered and compact composite films with one-dimensional carbon nanotubes (CNTs). The self-standing films show an optimized volumetric capacitance of 521.0Fcm^-3 with only 10 wt% of CNTs, which is attributed to dramatically enhanced electrical conductivity beyond the electrical percolation threshold, high dispersion of pseudocapacitive V2O5·nH2O nanosheets, and high mass density of the films. All-solid-state flexible SCs made of V2O5·nH2O/CNTs films show a maximum energy density of 17.4WhL^-1. 展开更多
关键词 flexible supercapacitors volum etric capacitance two - dimensional nanosheets vanadium pentoxide layered structure
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